Undelivered Mail Returned to Sender

This is the mail system at host smtp-2-3000.mail.infomaniak.ch.
I’m sorry to have to inform you that your message could not be delivered to one or more recipients. It’s attached below.
For further assistance, please send mail to postmaster.
If you do so, please include this problem report. You can delete your own text from the attached returned message.
The mail system
<censipaolo@libero.it>: host smtp-in.libero.it[213.209.1.129] said: 550 Invalid Recipient <censipaolo@libero.it> [smtp-19.iol.local; LIB_520] (in reply to RCPT TO command)
<gianmaterassi@libero.it>: host smtp-in.libero.it[213.209.1.129] said: 550 Invalid Recipient <gianmaterassi@libero.it> [smtp-03.iol.local; LIB_520] (in reply to RCPT TO command)
<orsinifrancesco1966@gmail.com>: host gmail-smtp-in.l.google.com[74.125.128.27] said: 550-5.1.1 The email account that you tried to reach does not exist. Please try 550-5.1.1 double-checking the recipient’s email address for typos or 550-5.1.1 unnecessary spaces. Learn more at 550 5.1.1 support.google.com/mail/?p=NoSuchUser oz38-20020a1709077da600b00939a0e68aa6si14169302ejc.418 – gsmtp (in reply to RCPT TO command)
<josursem@quicknet.nl>: host mxin5.ziggo.nl[212.54.42.8] said: 550 5.1.1 MXIN501 mailbox josursem@quicknet.nl unknown ;id=gnXYpbbgfWSwDgnXYp9MQ2;sid=gnXYpbbgfWSwD;mta=mx8.tb;d=20230327;t=160940[CET];ipsrc=83.166.143.175; (in reply to RCPT TO command)
<marcobelli81@libero.it>: host smtp-in.libero.it[213.209.1.129] said: 550 Invalid Recipient <marcobelli81@libero.it> [smtp-23.iol.local; LIB_520] (in reply to RCPT TO command)
<gigio69e@libero.it>: host smtp-in.libero.it[213.209.1.129] said: 550 Invalid Recipient <gigio69e@libero.it> [smtp-20.iol.local; LIB_520] (in reply to RCPT TO command)
<ireno.faranda@virgilio.it>: host smtp-in.virgilio.it[213.209.1.130] said: 550 Invalid Recipient <ireno.faranda@virgilio.it> [smtp-30.iol.local; VIR_520] (in reply to RCPT TO command)
<mikiros@virgilio.it>: host smtp-in.virgilio.it[213.209.1.130] said: 550 Invalid Recipient <mikiros@virgilio.it> [smtp-37.iol.local; VIR_520] (in reply to RCPT TO command)
<robbie.2007@live.nl>: host eur.olc.protection.outlook.com[104.47.18.161] said: 550 5.5.0 Requested action not taken: mailbox unavailable (S2017062302). (in reply to RCPT TO command)
<sebapilo@hotmail.it>: host eur.olc.protection.outlook.com[104.47.18.161] said: 550 5.5.0 Requested action not taken: mailbox unavailable (S2017062302). (in reply to RCPT TO command)
<loesboerkamp@live.nl>: host eur.olc.protection.outlook.com[104.47.22.161] said: 550 5.5.0 Requested action not taken: mailbox unavailable (S2017062302). (in reply to RCPT TO command)
<stenan@tiscali.nl>: host mx.kpnmail.nl[195.121.65.158] said: 554 5.7.1 recipient ‘stenan@tiscali.nl’ not known (in reply to RCPT TO command)